The present invention relates to a method for production of a modular building unit. Individual modules or units are at least substantially completed in a factory environment according to a predetermined design, after which they are transported to a proposed building site where they are set in place as a single module structure, or are coupled to other modules to yield a composite building. A significantly short period of time is consumed at the building site due to the high degree of completion of the unit achieved at the factory.
Modular concepts of construction, in which individual building modules are pre-fabricated, moved to a building site, and secured to additional modules to produce a desired structure are well established in the art. Similarly other known modular techniques involve remote prefabrication of components followed by component erection and completion of the structure at the building site. Generally speaking, however, both of the noted prior modular concepts have been fraught with problems and/or inherent limitations, such that the use of same has been severely limited. Specifically, while transport of a prefabricated module has precluded use of many conventional materials and has limited architectural design due to dimensional and structural considerations, prefabrication of components only, through less stringent in transport restrictions is both labor intensive and time consuming at the building site.
Exemplary of prior attempts at prefabrication of modules include the manufacture of rectangular-shaped modules which are limited in design and use by virtue of the necessity for supports internally of the modules. Such internal supports limit coupling of modules, restrict placement of internal walls within the module, or protrude into the intended useable interior where the supports must be enclosed, presenting aesthetically undesirable interior module features. In general, necessity for the internal supports has been dictated by lack of structural integrity of the system, per se, and in fact, one such system employs one or more temporary vertical supports during the manufacture of the module which remain in place until the modules are connected into a composite structure, at which time additional hidden supports are provided, adequate to permit the removal of the temporary internal supports, whereby an unobstructed interior of at least a portion of the composite structure is achieved.
Other systems avoid the above noted problem by designing the module so that critical support elements are located around the exterior of the module. In these systems, though the interior of the modules may be unobstructed, the exterior becomes potentially aesthetically unappealing. Further, in both of the above described systems, the structural frames employed limit the modules to use in a totally cubic deployment.
Due to the lack of structural integrity of the individual prefabricated modules of the prior art, individual modules are generally assembled into a composite building with the aid of tensioning cables, tie rods, rigid support couplings, support beams that extend across joints between modules and the like. These various means that are utilized to strengthen the prior art modules are adequate to perhaps properly unite adjacent modules into an overall structure, but are not adequate to overcome the patent lack of structural integrity of the modules per se which may be ascertained simply by movement about the interior of the structure. By way of exmmple, one outstanding nticeable feature of normal modular construction is a lack of stability and rigidity of the floor. Normally floors in prefabricated, transportable structures exhibit resilience when one walks thereacross due to a lack of strength or rigidity that is exhibited by conventional flooring.
Prior attempts to overcome the noticeable floor effect of prefabricated construction have included fabrication of the floor from a reinforced concrete floor or conventional materials at the building site, or the placement of structural reinforcement beneath the module at the building site, all of which detracts from the efficiencies of the system, per se. In fact, prior to the present invention, there has been no modular construction system that has employed a factory fabricated lightweight, reinforced concrete floor in the module which could be successfully transported from the factory to the building site without damage to the floor.
Prior art modular building systems involving fabrication of modules in a factory, followed by transport of the virtually completed module to a building site have followed two general structural techniques. One such technique includes exterior load bearing walls to achieve the degree of structural integrity and rigidity necessary for transportability of the module, and in fact, such modules generally include exterior load bearing walls of reinforced concrete, which are both architecturally and aesthetically limiting to the system. The second structural technique for such modular systems involves the inclusion of a load bearing structural framework to which non-load bearing exterior and interior walls are suitably affixed. Vertical load bearing columns are utilized in the framework, generally located at the four corners of the rectangular shaped module and at intermediate locations therebetween. The vertical columns may be secured between horizontal structural elements of the framework for the floor and roof of the module, or alternatively, the horizontal framework elements may be secured to the columns. Such structural framework arrangements of the prior art possess inherent disadvantages due to the requirement for intermediate supports between corner vertical supports, exposure of the vertical support columns around the exterior of the module, or the necessity to enclose the protruding vertical columns within the interior of the module.
All in all, reflecting on prior art modular construction systems, no system has existed heretofore in which basically conventional construction materials have been utilized as normally found in an office, an industrial building, or a dwelling totally constructed on site. With the present invention, however, such modules may be efficiently produced in virtually completed form in the factory, and are then transportable to the building site. At the building site the modules are placed in the appropriate configuration according to the intended design for the structure, and adjacent nodules are coupled to each other to ensure continuity of planar surfaces of the modules, such as the walls, floors, ceilings and the like, and generally without the necessity of significant additional structural coupling of the modules.
Insofar as the present process for producing a building module is concerned, the steps followed are quite efficient and quite accurate. The actual design of the individual module as dictated by the particular building design with which the module is to be employed may be produced with little or no deviation from the standard process of assembly. The process of the present invention is designed to permit multiple functions to be carried out simultaneously while each separate function is individually controlled to minimize chance for error, while at the same time affording great overall flexibility.
Though the process of producing a building module according to the present invention follows a production line technique, and production line techniques generally have been known and used heretofore for production of building modules, there is no known prior art that is believed to anticipate or suggest the present invention. Exemplary of the known prior art are the following United States patents.
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